This invention relates to a mechanism for preventing misoperation in a manual transmission which permits change from a two-wheel drive operation to a four-wheel drive operation and vice versa, and more particularly to a mechanism for preventing a select-operation to a low speed gear during a two-wheel drive operation and also preventing change from a four-wheel drive operation to a two-wheel drive operation especially at a low speed geared position upon running on a steep slope, sandy place and rough road.
The low speed gear is usually employed for running in a four-wheel drive operation, and during such a running operation, load accompanied by power transmission is charged on each differential gear for front and rear wheels. Therefore, overload is prevented from being applied to one of both differential gears. However, when the low speed gear is used during a two-wheel drive operation, the whole load is applied to the differential gear of the drive wheel. Accordingly, it is required to employ differential gears and drive shafts which are able to withstand larger load in comparison with those of a usual two-wheel drive vehicle having no low speed gear. As the result, common differential gear and drive shaft cannot be employed in a vehicle which permits change from a two-wheel drive operation to a four-wheel drive operation and vice versa.